Yu-lan Wei

Huazhong University of Science and Technology, Wu-han-shih, Hubei, China

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Publications (9)0 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To explore the feasibility and safety of microdrop-vitrification for epididymal spermatozoa obtained by percutaneous epididymal sperm aspiration (PESA) without cryoprotectants. We treated the epididymal sperm samples from 22 patients by conventional freezing (Group 1) and microdrop-vitrification without cryoprotectants (Group 2), and evaluated the effectiveness of the two methods by comparing their revival rate, retrieval rate and incidence of sperm nuclear DNA fractures. Motile sperm were found in all but 1 case in Group 1. The revival rates of the frozen sperm were low in both Groups 1 and 2 ([18.16 +/- 9.38]% vs [21.99 +/- 10.95]%, P > 0.05), but statistically significant differences were shown between the two groups in the retrieval rate ([58.39 +/- 12.67]% vs [70.82 +/- 14.94]%, P < 0.01). Before freezing, nuclear DNA fractures existed in the epididymal sperm samples of all the 22 patients, comet sperm were seen after unicellular gel electrophoresis, and the incidence of sperm nuclear DNA fracture was (26.68 +/- 9.45)%. After freezing, no increase was observed in the incidence of sperm nuclear DNA fracture in either Group 1 or 2 ([28.68 +/- 12.54]% vs [27.64 +/- 10.70]%, P > 0.05). Microdrop can be used as a suitable freezing carrier for a low number of sperm, and cryoprotectant-free vitrification with microdrop may be a simple, safe and effective method for the cryopreservation of a low number of epididymal sperm.
    Zhonghua nan ke xue = National journal of andrology 12/2010; 16(12):1089-94.
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    ABSTRACT: Objective To discuss the reason why human MII oocytes failed to fertilize after IVF and ICSI. Methods The unfertilized human MII oocytes were collected 24-48 h after IVF and ICSI and stained for immunoflurescence and PI counterstain. The types of fertilization failure were identified under the fluorescence microscopy. Results About 55.8% oocytes in IVF were found no sperm in them, which were more than that in ICSI (9.7%) (P<0.01). About 14.9% oocytes in IVF and 58.1% in ICSI displayed oocyte activation failure. The difference was significant (P<0.01). Defects in pronuclear formation and/or migration was found in a similar proportion of oocytes both after IVF (25.3%) and ICSI (32.3%)(P>0.05). There were 3.9% oocytes with other abnormalities were observed in IVF but none in ICSI. Conclusion The main reason of fertilization failure after IVF was no sperm penetration. However fertilization failure after ICSI was mainly associated with incomplete oocyte activation.
    Journal of Reproduction and Contraception 03/2010; 21(1):9-15. DOI:10.1016/S1001-7844(10)60009-0
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    ABSTRACT: To examine the influence of cryoloop on the spindle and chromosome configurations of human oocytes cryopreserved in the germinal vesicle (GV) and metaphase II (M II) stages, as well as on the survival rate and potential for in vitro maturation (IVM). GV oocytes were randomly assigned into a control group (matured in vitro into the M II stage), a GV cryopreserved group (cryopreserved in the GV stage and then matured in vitro), and an M II cryopreserved group (matured in vitro and cryopreserved in the M II stage). After cryopreservation and IVM, immunostaining of the tubulin and chromatin was performed followed by visualization using laser scanning confocal microscopy (LSCM). A significantly higher survival rate was observed in the GV cryopreserved group than in the M II , but the maturation rate showed no significant difference between the GV cryopreserved group and the control (P > 0.05). Compared with the control group, there was a statistically significant decrease in the rates of normal meiotic spindles and chromosomes in the GV cryopreserved group (P < 0.05). A significantly lower rate of normal spindles was noted in the M II cryopreserved group than in the control, but no statistical difference was shown in the rate of normal meiotic chromosomes between the two groups (P > 0.05). Cryopreservation by cryoloop has a damaging effect on the spindle and chromosome of human oocytes in the GV and M II stages.
    Zhonghua nan ke xue = National journal of andrology 06/2008; 14(6):498-502.
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    ABSTRACT: To assess the effects of the nuclear status of day 2 preembryos on day 3 embryo quality and implantation potential and to weigh its clinical value in the human in-vitro fertilization-embryo transfer (IVF-ET) program. Embryos obtained from 409 fresh conventional IVF-ET/ICSI cycles from July to October 2006 were assessed retrospectively. Day 2 preembryos were classified according to the number of nuclei in each blastomere in 3 groups: grade A with only mononucleated blastomeres, grade B with one or more blastomeres containing no visible nucleus, and grade C with one or more multinucleated blastomeres. Comparisons were made of the rates of arrested embryos and excellent embryos on day 3 as well as of the pregnancy outcome and implantation potential of those in whom cohorts of similar nuclear scoring embryos were transferred. There were fewer arrested embryos and more excellent embryos on day 3 in grade A than in grade B and C (P < 0.01), and so were there in grade B than in grade C (P < 0.01). Among the 234 cycles in which all the transfer embryos were derived from a similar day 2 nuclear scoring, 51 cycles originated from grade A embryos (group A) and 183 from grade B (group B), with similar clinical pregnancy rates between the two groups, while the implantation rate was higher in group A than in B (P < 0.05). Day 2 nuclear scoring can be used to predict the devel- opment and implantation potential of embryos. A combined evaluation of day 2 nuclear scoring and day 3 embryo morphology helps identify the most viable embryos and reduce the number of embryos for transfer.
    Zhonghua nan ke xue = National journal of andrology 01/2008; 14(1):26-9.
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    ABSTRACT: To study the effect of maternal age on meiotic spindle and chromosome configuration of oocytes. Spindle and chromosome configuration was examined in day 1 unfertilized human oocytes after in vitro fertilization (IVF) and intracytoplasmic sperm injection(ICSI) by immunocytochemistry and visualized by laser confocal microscopy. Statistically significant differences were observed on normal spindle and chromosome configurations of oocytes between 25-29 maternal age group (33% and 31%, respectively), and 30-34 age group (P< 0.05) as well as 35-40 age group(0%, P<0.01). The incidence of abnormal spindle and chromosome configurations of oocytes from 30-34 and 35-40 maternal age groups was much higher than that of oocytes from 25-29 age group (P<0.01, P<0.05). Incidence of abnormal spindle and chromosome configuration of oocytes is related to maternal age. It could be an important reason of age related oocyte aneuploidy.
    Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 03/2007; 24(1):6-9. DOI:10.1016/S1472-6483(11)60540-3
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    ABSTRACT: Retrospective study of the results of ICSI (intracytoplasmic sperm insemination) with frozen sperm obtained by PESA (percutaneous epididymal sperm aspiration) was performed in 27 patients. With conventional freezing method, sperm from diagnosing PESA and the remaining motile sperm after treating cycle were frozen. After frozen-thawed and ICSI process, fertilization rate, implantation rate, clinical pregnancy rate were compared and other outcomes including pregnant combinations and parameters of newborns of experimental group (which used frozen-thawed sperm) and control group (which used fresh PESA sperm) were analyzed respectively. One hundred and sixty three and 1 157 oocytes of stage M II were injected respectively in the experimental group (15 cycles) and control group (100 cycles), and fertilization rate of experimental group was prominently higher than that of control group (84.05% vs 73.29%, P < 0.05), while implantation rate and clinical pregnancy rate were of no difference from the control, respectively (23.07% vs 15.73%; 53.33% vs 37.00%, P > 0.05). The differences in newborn's weights between two groups were of no statistical significance (P > 0.05). In the experimental group, eight clinical pregnancies were achieved including 5 live deliveries and 3 ongoing pregnancies, 37 clinical pregnancies including 30 deliveries with only 1 fetal death, 3 ongoing pregnancies and 4 abortions in the control group. Neither vital pregnant combinations nor neonate malformations were found in both groups. ICSI using frozen-thawed sperm obtained by PESA is an economic effective and safe method to treat azoospermia. Recovering rates of frozen sperm form PESA should be further increased.
    Zhonghua nan ke xue = National journal of andrology 05/2006; 12(5):443-5, 449.
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    ABSTRACT: To assess the outcome of thawing human cleaved embryos from cryopreservation by vitrification. A total of 957 day 2 or day 3 embryos from 219 patients were thawed after vitrification with ethylene glycol 5.5 solution and 0.25 ml straw between Jan 2003 and Jun 2005, 514 embryos were recovered and transferred in 178 patients. The survival rate of thawing embryos and the clinical pregnancy rate after transfer was 72.2% and 19.7% respectively. Twenty-two healthy babies were born from 16 deliveries, including 12 girls and 10 boys, 6 pregnancies ended in miscarriage and another 13 are ongoing. Vitrification method is an alternative for cryopreservation of human cleaved embryos because of high effectiveness, convenience and good cost efficiency.
    Zhonghua fu chan ke za zhi 11/2005; 40(10):682-4.
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    ABSTRACT: To investigate the mechanism of insulin-like growth factor-I (IGF-I) affecting adhesion of trophoblast cells in vitro. Trophoblast cells were obtained from early gestation at artificial abortion to set up the in vitro trophoblast cell adhesion model. The trophoblast cells were incubated with or without 10 nmol/L IGF-I and were divided into three groups (10 nmol/L IGF-I, 10 nmol/L IGF-I + alpha v beta3Ab, and control). The amount of adhered cells was assessed by examining absorbency using enzyme-linked immunoassay. Morphological changes were studied using scanning electron microscopy. The expression of phosphorylated focal adhesion kinase was determined by immunocytochemistry. After serum-starved trophoblast cells were incubated only with IGF-I, the mean absorbency was 0.491 +/- 0.049, obviously higher than control 0.198 +/- 0.022 and the difference was dramatic (P < 0.01). When cells were pre-treated with antibody against alpha v beta3 integrin and then incubated with IGF-I, the mean absorbency was only 0.184 +/- 0.031, distinctly lower than that incubated with IGF-I, and the difference was significant (P < 0.01), however, compared with control, there was no significant difference (P > 0.05). Scanning electron microscopy highlighted a dramatic increase in lamellipodial formation and extension in the IGF-I treated cells compared with control. Immunocytochemistry staining showed phosphorylated focal adhesion kinase was expressed in the trophoblast cells treated with IGF-I. 10 nmol/L IGF-I can significantly stimulate trophoblast cells adhesion to fibronectin, but antibody against alpha v beta3 integrin obviously blocks its adhesion. IGF-I can stimulate lamellipodial formation and extension at the adhesion sites, and promote adhesion of trophoblast cells to fibronectin by activating phosphorylated focal adhesion kinase.
    Zhonghua fu chan ke za zhi 07/2005; 40(6):392-5.
  • Gui-jin Zhu, Yu-lan Wei, Juan Hu, Qun Liu
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    ABSTRACT: To investigate the incidence of microorganism contamination in in vitro fertilization-embryo transfer (IVF-ET) and to determine the sources of microorganism. Two thousand one hundred and seventy-four cycles of in vitro fertilization from January 1999 to June 2003 were evaluated retrospectively and bacterial cultures were performed in 61 semen samples from asymptomatic men with normal semen parameters and in 34 follicle fluid samples from infertility women through oocyte picking up procedures. Microorganisms were found in 11 cases. The incidence of their contamination in IVF culture system was 0.51% and the most common microorganisms were Escherichia coli and fungi. Microorganisms were detected in 97% of unprocessed semen, 10% in processed semen, 6% in semen mixed with media and 9% in follicle fluid. The incidence of microorganism contamination was 0.51% and the most common microorganisms were Escherichia coli and fungi. Semen may have the potential to contaminate IVF culture system.
    Zhonghua fu chan ke za zhi 07/2004; 39(6):382-4.